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Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.

PMID 25943678 (2015): heat acclimatization — Performance in heat (study note for endurance athletes).

Last updated/Feb 23, 2026, 10:34 PM

Study note • PMID 25943678

Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.

Scandinavian journal of medicine & science in sports2015 • DOI 10.1111/sms.12409
Evidence C60/100
Action 2: Consider

Worth trying if it fits your goal and context.

ELI5

In plain language

This study investigated if well-trained cyclists improve V O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions. (controlled study; n=9 well-trained cyclists).

The abstract doesn’t indicate a clear change in Performance in heat under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: This study investigated if well-trained cyclists improve V O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions.
  • The abstract doesn’t indicate a clear change in Performance in heat under the tested conditions.
  • Population: n=9 well-trained cyclists.
  • Protocol cues (title/abstract): 2 weeks • 3 min • 4 min • 2 m • 4 km.

Protocol

Protocol (as reported)

  • Intervention/exposure: heat acclimatization (vs comparison group).
  • Dose/time/duration cues in abstract/title: 2 weeks • 3 min • 4 min • 2 m • 4 km.
  • Outcomes: Performance in heat.
  • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.

Fit

Who it helps, and who should skip it

Who it helps

  • Athletes similar to the study population (n=9 well-trained cyclists) working on heat.
  • Athletes who can measure Performance in heat with a repeatable workout or time-trial effort.

Who should skip

  • If you have symptoms or conditions that make the intervention risky, get professional guidance.
  • If you’re near race day and can’t safely test, defer the experiment.

Methods

What the study actually did

  • Design: controlled study.
  • Population: n=9 well-trained cyclists.
  • Comparator: comparison group.
  • Outcomes measured: Performance in heat.
  • Protocol cues mentioned: 2 weeks • 3 min • 4 min • 2 m • 4 km.
  • Source: PubMed PMID 25943678 (2015) — Scandinavian journal of medicine & science in sports.

Results excerpt

What the abstract reports

After heat acclimatization, TT performance in the heat was improved by 16%; however, there was no change in the HA group in V O 2 m a x (4.79 +/- 0.21 L/min vs 4.82 +/- 0.35 L/min), peak aerobic power output (417 +/-…

Note: excerpts are short; for full context, read the paper.

Limits

Limitations & bias

  • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
  • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
  • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
  • This is performance information, not medical advice.

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Sources